They make good bioindicators of the quality of water in rivers and ponds as many rely on high-quality water to fully develop their larval stages in their life cycles. These two teacher resources have practical information for restoring streams for native fish: Planning for change and Planting stream edges.
These could be adapted when looking at aquatic insects, as a healthy environment for fish also means a healthy environment for these insects. Read about how students helped restore mauri to the Oruarangi Stream in this PSP citizen science project. The student activity Observing freshwater macroinvertebrates gets students out to their local stream, capturing, observing and developing classification systems based on what they find.
This could be combined with an activity to identify what is an insect and what is not. Visit our We love bugs! Pinterest board with links to resources and community activities.
NIWA has an online Stream Health Monitoring and Assessment Kit that enables non-scientists to collect consistent, scientifically valid information from small rural streams. Manaaki Whenua — Landcare Research has an online Freshwater invertebrates guide to assist community groups with monitoring freshwater invertebrates in New Zealand and What is this bug? There is also a range of pages providing general information and fact sheets under Invasive invertebrate threats ants, mosquitoes and wasps and Invertebrate systematics includes ants, beetles, weevils, stick insects and scale insects and more.
Thank you to the New Zealand insect cards project for its support in the writing of this content. Original material developed with support from the New Zealand Entomological Society.
To buy a set of the Insects of New Zealand playing cards, see the list of stockists here. Lepidoptera—unlikely, due to typically small, natural populations.
Most of the aquatic lepidopterans are hydrophilic and belong to the Pyralidae. Many semi-aquatic species are miners and borers in the tissues of aquatic plants. Consumption of pyralids has been recorded for the people living in the town of Tulancalco, near Mexico City [ 17 ].
Hymenoptera—unlikely, due to relatively small populations. Several families within the suborder Apocrita contain species associated with water. The latter are small wasps and all are parasitic on various aquatic hosts, which include dipterans, beetles, bugs especially gerrids , damselflies and caddisflies.
Six insect orders are likely to contain candidate species. Their merits are as follows—note that because of the paucity of scientifically verified information, anecdotal information from the popular press and web-based sources is also included. Where known, nutritive values are also given. These details should be examined alongside the global list of aquatic insect species given in the Appendix for which there are records of entomophagy.
A point to note is that most of the global Biological Regions support aquatic species that have been recorded as edible and that belong to the six orders. The same may be true for the relatively low species count in the Nearctic. Ephemeroptera —There are more than species of mayfly. The majority are lotic, but while many species live in small to medium-sized streams, huge, natural, mass emergences have been recorded from large rivers e.
These events are seasonal but, as the adults are attracted to lights and bridges, there are opportunities to gather them, in bulk, for processing and storage. Large lentic species, such as Hexagenia limbata Ephemeridae , perhaps have the potential to be raised in culture as their development is highly temperature dependent and they feed by collecting fine-particle organic detritus.
The species has been observed to complete its life cycle in 17 weeks in warm canals in Utah and, in laboratory tanks, this has been reduced to 13 weeks [ 19 ]. There is anecdotal evidence that adult mayflies are harvested and eaten in many parts of China and Japan, and also in New Guinea and Vietnam.
Both the nymphs and adults of Ephemerella jianghongensis are eaten in Yunnan Province, China [ 7 ]. In Malawi, people make a paste, called kungu, out of mayflies Caenis kungu mixed with mosquitoes, which is formed into dried cakes.
On the shores of Lake Victoria, mayflies of the genus Povilla Polymitarcyidae are dried for subsequent use in meal preparation. There are also tales of 17th century Incas eating nymphs of Euthyplocia Euthyplociidae and possibly also Campylocia either raw or in a spicy sauce [ 22 , 23 ].
Odonata —There are almost species of odonate, distributed from the tropics, where the greatest numbers and diversity occur, to the tree-line in polar regions [ 13 ]. Nymphs of six to seven species are eaten in China, with the most common being Crocothemis servilia , Gomphus cuneatus, and Lestes praemorsa [ 24 ]; see also the Appendix.
In Thailand, Hanboonsong [ 25 ] recorded species from four genera as being commonly eaten Aeshna , Ceriagrion , Epophtalmia, and Rhyothemis. In total, some 26 species of odonate are known to be eaten in the Oriental Region see the Appendix. Of note is the preference for species of Libellulidae 17 in the Orient but for species of Aeschnidae 7 in the Neotropics see Appendix.
Based on odonates alone, there is strong evidence of existing entomophagy in many parts of the Orient, and also in the Neotropics at least 15 species eaten. In the terraced rice paddy fields of Bali, the local people catch adult dragonflies using the sticky sap from jackfruit or frangipani trees.
The sap is either painted on to the tip of a thin stick or formed into a small ball which is then whirled around on a string. In Laos, the preferred species is Anax guttatus Aeshnidae , which is captured using a candle suspended over a dish of water. Dragonfly nymphs are also eaten, but more rarely [ 26 ]. There may be some potential for suitable lentic species to be raised in tanks.
However, most species have a long life cycle and the nymphs require live invertebrate food—although mass-reared mosquito larvae could provide a convenient source.
Hemiptera —Globally, there are around known species of aquatic and semiaquatic Hemiptera grouped by some into the suborder Heteroptera and, of these, a number are eaten. In many parts of Asia, belostomatids giant water bugs are a well-liked delicacy [ 28 ], but they are also eaten in most other parts of the world [ 3 , 9 ].
This species can be readily attracted to lights but is becoming rare. Researchers at Khon Kaen University in Thailand have reported some success with a new rearing technique for L. There is also potential for some, largely lentic, hemipteran species to be raised in tanks, although production on a commercial scale has still not been achieved [ 30 ].
However, very recently there has been some success at farming L. Shantibala et al. In Thailand, Hanboonsong [ 25 ] has recorded two species of belostomatid, the water strider Cylindrostethus scrutator , three species of Nepidae, and two species of backswimmer Notonectidae: Anisops barbutus and A.
In Thailand, school children are encouraged to raise insects, including L. More than half of the species consumed are collected during the rainy season May—July when their pond and wetland habitats are most prevalent in the landscape.
Edible hemipterans particularly attracted to these temporary waterbodies include naucorids creeping water bugs , notonectids back-swimmers , and gerrids water striders [ 9 ]. During the rest of the year, villagers supplement their diets with commercial, mass-reared insects, such as crickets. There exist several techniques for raising smaller hemipterans for research purposes in the laboratory. For example, the water strider Limnogonus fossarum fossarum , common in the Oriental Region, can yield more than five generations per year, provided that it is fed suitable live prey species [ 33 ].
McPherson [ 34 ] outlined a technique for rearing Notonecta hoffmanni in the laboratory. It is possible that some of these protocols could be scaled up for greater yield. Coleoptera —Of the close to , species of beetle, roughly 1. The latter live in a very wide spectrum of habitats coldwater springs to salt-marshes but, while they may be important to these ecosystems, they do not reach the levels of density or biomass seen in other orders, such as the Trichoptera and Diptera [ 35 ].
Lotic species are unlikely candidates for mass harvesting due to typically small, dispersed natural populations although riffle beetles, Elmidae, may be an exception; [ 36 ]. However, some lentic species can occur in quite high densities e. Globally, upwards of 78 species, in 22 genera, have been recorded as being edible.
Mexico leads with 36 species eaten, followed by China 26 and Japan 15 [ 36 ]. Certain genera are consumed more than others, with 22 species within the dytiscid genus Cybister confirmed as eaten, worldwide, and also 12 species of the hydrophilid genus Hydrophilus [ 9 ]. In Thailand, Hanboonsong [ 25 ] reports three species of Hydrophilidae and eight species of Dytiscidae as commonly eaten.
In China, they are consumed more for their anti-diuretic effect, although Cybister tripunctatus has a high fat content However, this species, like a number of other exploited aquatic insects, is on the decline, and is on the Red Data List in Japan [ 38 ].
Ramos-Elorduy [ 17 ] has reported that, in Mexico, 14 insect species are considered to be threatened. In large part, this decline is due to over-harvesting of wild populations. Clearly, culturing techniques need to be developed to compensate. Such an approach has multiple benefits for local populations, not only directly through food but also for local economies, as excess beetle biomass can be sold to ready national and international markets.
As a comparison, as early as in South Africa, Van der Waal showed the sale of grasshoppers to be a business worth over 1 million dollars, annually [ 39 ]. More recently in Uganda, Agea et al. Such data are not readily available for aquatic insects.
However, in Guangdong, China, water beetles sold in local markets are now being hatched in special nurseries [ 30 , 41 ]. Two problems hinder the mass rearing of water beetles: provision of an ample and continuous supply of live food; and surface-rippling resulting from tank aeration requirements that interfere with the respiration of small beetle larvae. Using Dytiscus sharpi as a model species, Inoda and Kamimura [ 42 ] have designed a new open-aquarium system that largely addresses the second issue.
Adequate supply of live food can be achieved through parallel mass rearing of mosquito larvae see next section. Diptera —There are around , known species of true two-winged fly, with many more thought yet to be described. Within the order are several large aquatic families that are important to natural and human-centric ecosystems: Tipulidae craneflies ; Culicidae mosquitoes ; Chironomidae non-biting midges ; and Simuliidae blackflies.
In the life cycle, the adults are typically terrestrial, with the larvae and pupae living in water [ 13 ]. In some species and habitats, population sizes can be vast and affect humans in diverse ways—for example, negatively, as vectors of disease, and, positively, as a food source.
Tipulidae : Craneflies occur in virtually every type of freshwater habitat and are especially abundant in shallow margins where their larvae play an important role in shredding riparian leaf litter. With over 15, species, the Tipulidae represents the largest family of Diptera.
In temperate regions, the life cycle is typically one year which might render them unsuitable for mass rearing. However, the decent size of many species 1 to 2 cm could make them viable especially as they have the potential to be raised in shallow, polythene-lined depressions filled with water and leaf litter. Emerging adults are easy to collect with sweep-nets and could also represent an important food source for local communities, as they do for many bird, mammal, fish, amphibian, and reptile species [ 43 ].
However, their global distribution, rapid development, and occurrence at very high densities make them prime candidates for entomophagy, in several ways.
For example, mass emergences of adult culicids, such as those that take place on the Arctic tundra [ 44 ], but which are not yet harvested. Included, here, should also be the example of the culicid sister-group, the Chaoboridae, which are sustainably harvested on the shores of Lake Victoria, by local Luo villagers [ 45 ]. Mass rearing and harvesting of culicid larvae should be possible through scaled-up methods already proven in the laboratory e.
Chironomidae : Non-biting midges have a global distribution and often occur at very high densities, sometimes as a consequence of human activities, for example pollution of water bodies with organic wastes.
There are thought to be perhaps 20, species in total, with around having been formally identified and named. Chironomids are highly speciose, often exceeding 80 species at a single site, with most aquatic predators feeding on them at some stage in their lives [ 49 ]. Many species are small, with larvae less than 1 or 2 mm in length, although some may exceed 1 cm e. A potential problem with mass rearing these midges is that contact with adults or larvae sometimes causes allergic reactions, particularly in farmers and fish-food handlers [ 51 ].
Chironomids are also used in a number of real-world applications including recycling of farm manure and waste-lagoon purification where, over a five month period, the larval yield was 51 kg, wet weight [ 52 ].
In Hong Kong in , Shaw and Mark reported on a large Recorded instances of chironomids being eaten directly are largely anecdotal. Chironomids are also eaten together with chaoborids as the adults of both emerge at the same time on the shores of Lake Victoria see above; [ 21 ].
Simuliidae : Blackflies comprise a cosmopolitan family of biting dipterans of great importance in many parts of the world as bloodsuckers and vectors of parasites such as filarial worms. The larvae and pupae are confined to running waters where they attached themselves to firm, usually smooth substrates. There are around known species. Collection of larvae and pupae can be done easily by brushing them off substrate surfaces into downstream nets.
Despite this simple method, there appear to have been few attempts to harvest this naturally occurring biomass. Moreover, blackfly larvae readily colonize flat, artificial substrates placed in areas of fast current, providing an alternative harvesting technique. Further, adult blackflies are attracted, in large numbers, to lights at night and thus can be netted.
There is a single report of blackfly larvae being eaten as a delicacy by some Karen hill-tribes in northern Thailand [ 56 ].
Because of their ability to spread parasites, blackflies should only be eaten after cooking, with the same applying to culicids. Simuliids are known to be difficult to rear under artificial conditions. However, Raybould [ 57 ] recorded some success with Simulium damnosum , using a laboratory approach, and Marr [ 58 ], similarly, but using a modification to a natural breeding place. Trichoptera —Of the approximately known species of caddisfly, all but a few live in freshwater lotic or lentic habitats.
Within these, they have become adapted to a wide range of conditions and, where favorable, their larvae can occur at high densities. Consequently, the adults often emerge synchronously and in large numbers, and are strongly attracted to lights. These mass emergences can be a nuisance around urban rivers and lakes e.
Lawrence, Winnipeg, and Niagara rivers in Canada [ 59 ]. However, such events provide opportunities for harvesting—although, again, there are few records of this happening. A particular habitat that promotes very high larval densities of net-spinning families e. In a manner similar to that described, above, for blackflies, concrete slabs or slates inserted into suitable rivers can replicate such habitats from which late-instar larvae and pupae can be gathered.
There is also the potential for larger, lentic species to be raised in tanks or small artificial ponds—especially those that emulate vernal woodland pools. Despite the potential of caddisflies to be used in the human diet, by virtue of their accessibility and the size of their larvae, there are few records of entomophagy.
The most commonly eaten species are Stenopsyche griseipennis , Parastenopsyche sauteri , and Cheumatopsyche brevilineata see Appendix , and those collected from the pristine Tenryu River are particularly prized.
The high production of larvae in this river is due to a high nutrient load carried down from an upstream lake [ 61 ]. It is clear from the above examples that there is a dichotomy of purpose in the consumption of aquatic insects by humans.
The other purpose is as part of the staple diet of indigenous, largely poor, peoples chiefly from tropical and subtropical countries.
Often the dietary contribution is seasonal, dictated by the timing of the life history stages of the insects. As noted, compared with terrestrial insects there is relatively little information on the occurrence of aquatic insects in the human diet and the same is true for analysis of their nutritional value. To this end, Table 3 shows the average daily requirements of essential dietary components together with approximate yield potentials from eating dried terrestrial insect bodies.
Several observations are noteworthy. First, the protein yield is quite high, with one cup-full g of dried insects yielding close to the daily recommended adult reference intake ARI. Second, in contrast, the yield of carbohydrate is very low it would require 26 cups-full, or 5. Third, the ranges in yield potential are quite wide especially for total fat and fiber —presumably dependent on the type of insect analyzed.
Last, roughly 1. Clearly, one would not eat insects to acquire carbohydrates, but would for protein. Indeed, aquatic insects in general tend to be excellent sources of protein, for example: Ephemeroptera Eating insects in combination with another source of carbohydrate such as rice, millet, or cassava could help approach a more balanced diet. In addition to the above components, Bergeron et al.
A report by the FAO found that many edible insects are good sources of minerals such as iron and zinc. Deficiencies of iron and zinc are common health disorders worldwide and insects could contribute to preventing these [ 8 ]. Comparison of the average daily requirements in the human diet with potential yield from eating insects. Note that the yield potential values are based on a variety of studies, using a range of methodologies and different insect species.
As such, the yield ranges tend to be large and should be regarded as approximations only. Bell et al. They found that a dietary fatty acid composition more akin to that of the invertebrates might be beneficial for growth, development, and the prevention of pathologies in farmed parr.
Consumption of such invertebrates might well be expected to bestow similar advantages to humans. In a study of the fatty acid composition of aquatic and terrestrial insects, Fontaneto et al. Ayieko et al. They found that in hot climates high food spoilage is commonplace. Using termites and lake-flies dipterans and mayflies captured along the shores of Lake Victoria, they cooked these insects in the laboratory under different conditions: baking, boiling, steam cooking under pressure.
The end products e. Moreover, the latter may benefit from certain insect properties such as antioxidant and antibacterial activity. In humans, the available nutrients in insects have been shown to contribute to an acceptable diet. The same also applies to animal feed although, again, the data come mostly from studies on terrestrial insects [ 72 ]—however, the possible application to aquatic insects was suggested as early as [ 73 ].
Significantly, alongside grasshoppers, lake-flies can supplement essential vitamins and minerals necessary in cattle feed, including those that improve general herd and udder health vitamins E and A, Beta-carotene, and selenium; [ 74 ]. The stark contrast between insects and cattle is most evident when their respective conversion ratios are compared—although it should be noted that cattle are not amongst the highest converters [ 75 , 76 ]. Cattle need up to 18 kg of feed to produce 1 kg of edible meat.
Crickets require 2 kg of feed to produce 1 kg of edible meat [ 77 ]. Clearly, it would be more efficient to use insects directly as human food. Although use of aquatic insects is largely not yet on the feed-production radar, there is recognition that terrestrial insects can contribute. Indeed, insects have a similar market to fishmeal and are in use as feed in aquaculture and livestock, and in the pet industry.
As the production costs of this feed rise related to the decreasing supply of industrially caught fish and increase in aquaculture , the search is on for alternative and sustainable protein sources—which makes insects an attractive feed option [ 78 ]. Insects can contribute similarly to the poultry and beef industries, although there are still some financial issues as current production costs are high—Meuwissen [ 8 ] has shown that the production of mealworms is still almost 5 times as expensive as conventional chicken feed.
As for aquatic species, chironomids are used as fish food and can be grown using farm wastes, such as chicken manure [ 53 ]. Given the known issues with allergic reactions see above , there may be more potential for chironomids as animal feed than as human food. Interestingly, farmed marine fishes require highly unsaturated fatty acids HUFA in their prepared diets. The latter are usually absent from terrestrial insects, but are more common in aquatic insects which feed on aquatic plants and animals that are richer in HUFA.
Aquafeeds containing freshwater insects for example, mosquitoes would be advantageous [ 79 ]. Based on current knowledge, it is evident that some aquatic insects are, historically, already a significant part of the diets of many indigenous peoples. Access to this edible biomass is typically via harvesting natural populations at times dictated by species availabilities.
Knowledge of habitats and life cycles is fundamental for this and likely has become drawn into local folklore and tradition. However, based on this same information there exists potential for culturing edible species, using the simplest of materials and methods—such as creating artificial ponds for attracting migrating water-beetles, or raising odonates or placing flat tiles in running waters for colonization by net-spinning caddisflies or blackflies.
The method used submerged vegetation bundles set out as egg-laying substrates akin to mussel farming [ 80 ]. Parsons [ 81 ] estimated that an adult insect harvest of 10 kg and an egg harvest of 5 kg would have been attainable every two weeks per hectare of lake surface—a combined annual yield of almost metric tonnes, given a lake surface area of 10, hectares. Unfortunately, while there are descriptions of methods of mass-rearing insects in closed environments [ 54 ], precious few involve farming aquatic species.
Nevertheless, looking ahead, once techniques for obtaining aquatic insects in bulk have been developed, their yields can be subjected to the innovative processing protocols that have already been developed for terrestrial insects, such as crickets or mealworms. In , the Kenya News Agency reported on a thriving facility at the Jaramogi Oginga Odinga University of Science and Technology where crickets are being successfully raised in bulk to address the problem of malnutrition in Africa.
The operation plans to include other species in due course [ 82 ]. A very thorough review of this modern insect-based food industry is given by Dossey et al. Hanboonsong [ 25 ], further, points to the potential benefit of including locusts amongst the commercialized species. Not only can they be harvested in huge numbers during population outbreaks, but collecting them negates the use of pesticides. In some instances, demand has outstripped supply such that locusts are being brought into Thailand from neighboring countries, such as Cambodia [ 30 ].
A potential negative aspect in eating, especially raw, insects is the potential for transmission of zoonotic infections. There are over 8, species of aquatic insects in North America, all of which spend at least a portion of their life in a freshwater environment. These bugs can be found in a variety of habitats, from ponds and water features to streams and rivers. But which aquatic bugs are most common in the USA, and how can you identify them?
Dragonflies and damselflies are some of the most instantly recognizable aquatic insects in North America. Their elongated, brightly colored bodies, bulging eyes, and iridescent wings are a common sight on warm, summer days — but how can you tell a dragonfly from a damselfly?
The presence of mayflies is a great indicator of good water quality, as the early life stages of these pollution-sensitive insects take place in water. Mayflies are best known for their incredibly short lifespans, with adult insects surviving as little as one day.
Caddisflies are a group of silk-spinning, mothlike insects that spend their larval stages in freshwater habitats. They are common throughout the world, with around species of Caddisfly known to exist globally. Aquatic insects eat a variety of foods, depending on their species. Some eat decaying organic matter or plants, while others are predatory and will dine on other insects.
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